Device for administering an injectable product with a lockable dose metering mechanism

ABSTRACT

A device for administering an injectable product including a housing with a reservoir for the product, a delivery device, which can be displaced out of a release position and into an activating position and, from the activating position, executes a delivery movement via which a set product dose is discharged from the reservoir, and a dosing device that, for setting a product dose, can execute a dosing movement in dosing positions predetermined by detent engagement when the delivery device occupies the release position, wherein the delivery device, when in the activating position and when moving into the activating position, is coupled to the dosing device via a blocking engagement which prevents the dosing device in the respectively set dosing position from executing dosing movements.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation of International Application No.PCT/CH2005/000216, filed on Apr. 19, 2005, which claims priority toGerman Application No. 10 2004 020 374.1, filed on Apr. 23, 2004, thecontents of both of which are incorporated in their entirety byreference herein.

BACKGROUND

The present invention relates to device for dispensing, injecting,administering, infusing or delivering substances, and to methods ofmaking and using such devices. More particularly, it relates to a devicefor administering an injectable product which enables a dose to befreely selected by a user of the device. The injection device issuitable for situations in which the user self-administers the productand is able to select, i.e. set or choose, a dose individually withevery administration. More particularly, the injection device is of thetype suitable for administering insulin as a diabetic treatment, or foradministering growth hormone.

Patent specification EP 0 713 403 A1 discloses a syringe foradministering liquid pharmaceutical mixtures and other liquids whichallows a dose of liquid to be administered per injection to be set oncefor every injection. Specifically, a setting is made by a pharmacist.However, in the case of a patient who then has to use the syringe toself-administer the pharmaceutical liquid, it is difficult to change thedose once it has been set. The intention is to prevent an incorrect dosefrom being administered with the syringe. A syringe of this type is noteffectively useful in some treatments because an optimum or requisitedose may vary depending on, for example, the time of day, sportingactivities or the consumption of meals.

Injection devices which satisfy requirements of variable doses are knownfrom patent specifications WO 97/36625 and DE 199 00 792 C2, forexample. These two specifications relate to injection devices, each ofwhich has a conveying mechanism for dispensing the product, and a dosemetering mechanism for setting the product dose which can be conveyedand dispensed by the conveying device during a subsequent injection. Theconveying mechanism comprises a plunger, the forward stroke of whichconveys the product from a product reservoir, a plunger rod and a drivemember for the plunger rod. The drive member and the plunger rod engagewith one another so that a forward movement of the drive member causesthe plunger rod to move in the same way but the drive member performs areverse movement in the opposite direction until it reaches a triggerposition, from which another injection can be initiated. The triggerposition is determined by means of the dose metering mechanism, whichforms an adjustable dose metering stop for the drive member. Althoughthe known devices have proved to be efficient in practice, they couldstill be improved to make them more reliable in terms of minimizing therisk of incorrect doses.

SUMMARY

One objective of the present invention is to provide a device foradministering an injectable product which enables a dose to be freelyselected while reducing the risk of incorrect dosage.

In one embodiment, the present invention comprises a device foradministering an injectable product, such as a portable injectiondevice, which can be carried in a pocket. In one embodiment, the devicecomprises a housing with a reservoir for the product, a conveyingmechanism for conveying the product and a dose metering mechanismenabling a product dose to be freely selected for every injection. Thehousing itself may constitute the reservoir. However, the housing isdesigned as a housing compartment for a product container which may beof the type sold as standard in the form of a pre-filled ampoule. Theexpression “housing with a reservoir” should also generally beinterpreted as meaning a housing which forms a housing compartment for aproduct container in which the product container has not yet beeninserted.

The conveying mechanism is mounted, so that it can be moved, by and/orrelative to the housing. It may perform a conveying motion by which theproduct is conveyed out of the reservoir and dispensed. It can be movedrelative to the housing or at least a part of the housing into at leasttwo, and in some preferred embodiments, exactly two, different positionswhich are pre-defined, by stops. One of the positions is a triggeringposition from which the conveying movement is performed directly orafter first performing another movement. The other position is a releaseposition, from which the conveying mechanism can be moved into thetriggering position. In some preferred embodiments, the conveyingmovement and the movement into the triggering position are linearmovements, and in some embodiments, along a single translation axis. Insome embodiments, the movement out of the release position into thetriggering position is in exactly the opposite direction from theconveying movement. In some preferred embodiments, the conveyingmechanism is able to move backward and forward between the triggeringposition and the release position, and more particularly, may be able tomove exclusively in this manner. The movement out of the triggeringposition is initiated by manual pressure on the conveying mechanism andthe movement into the triggering position is activated by manuallyapplied tension. For simplicity, the movement to the release positionwill be referred to, in the following, as the re-setting movement. Thefact that the conveying mechanism performs a movement does not mean, inthe case of one preferred multi-part design of the conveying mechanism,that all parts of the conveying mechanism always perform the movement inquestion or that they perform a joint movement at all, although a jointmovement is preferred in at least certain phases and/or embodiments.

In some embodiments, the dose metering mechanism is mounted on orconnected to the housing, so that it is able to perform a dose meteringmovement relative to the conveying mechanism or at least a part of theconveying mechanism to set the product dose to be conveyed by theconveying mechanism. The product dose which can be set is pre-defined bydose positions into which the dose metering mechanism latches during thedose metering movement. The corresponding latched engagement may beformed by the housing or/and the conveying mechanism. The dose may beset in readiness when the conveying mechanism assumes the releaseposition and, in some preferred embodiments, only then. The pre-defineddose metering positions may be only two different dose meteringpositions, so that two different product doses can be administered atdifferent times of the day, for example. In other embodiments, more thantwo or a plurality of different dose metering positions are provided, toadapt to different situations and/or provide the option of enabling anindividual dose to be set for product doses to be administered for aheterogeneous group of persons.

In accordance with the present invention, in one embodiment, the dosemetering mechanism is coupled to the conveying mechanism by a blockingor locking engagement when the conveying mechanism assumes thetriggering position and also during the re-setting movement of theconveying mechanism. In the blocking engagement, the dose meteringmechanism is locked against dose movements relative to the conveyingmechanism in the previously set dose position. A forced movement out ofthe blocked dose position is only possible by applying anextraordinarily strong force and this results in the device being badlydamaged, which then makes it impossible to use the device foradministering the product any more.

One advantage of the present invention is that the dose is set in therelease position and a “subsequent dose” can not then be set in thetriggering position and the re-setting movement is also stabilized. Theblocking action in the triggering position is advantageous because thedevice can be safely manipulated for administering purposes because themanipulations needed to proceed with the administering action can notaccidentally lead to the set dose being adjusted. Although the dosemetering mechanism is guided tightly in the blocking engagement toprevent movements transverse to the direction of the re-settingmovement, a certain amount of clearance may be provided in principle, aslong as there is no possibility of causing an adjustment to the setdose. If the movement of the conveying mechanism out of the triggeringposition into the release position takes place in the direction oppositethe re-setting movement, as in some preferred embodiments, anotheradvantage is that, if no counteractions are encountered, this movementand hence the conveying movement is stabilized and thus prevents anyadjustment being made to the set dose inadvertently.

As mentioned above, in some embodiments the triggering position is astop position. For dose metering purposes, this stop position isadjustable in and opposite the direction of the conveying movement andthe maximum path length of the conveying movement is therefore alsoadjustable. The conveying mechanism and the dose metering mechanism,respectively, serve as a dose setting stop and the two dose settingstops delimit the re-setting movement of the conveying mechanism andthus determine the triggering position. This means that one of theconveying mechanism and dose metering mechanism, in some preferredembodiments, the dose metering mechanism, forms a stop which can bevaried in terms of its position. Examples of adjustable dose settingstops are disclosed in patent specifications WO 97/36625 and DE 199 00792 C1. Based on the reverse kinematics in terms of their paths, i.e. asdiscrete dose setting stops, the disclosed dose setting stops could alsobe provided on the conveying mechanism, in which case it would be enoughto provide a stop cam on the dose metering mechanism which is set in adose position by the dose metering movement.

In preferred embodiments of the present invention, the dose meteringmechanism is blocked due to the engagement of at least one guide and atleast one locating element. This ensures that, for each of the dosemetering positions, one of the conveying mechanism and dose meteringmechanism forms a guide and the other forms an locating element whichlock with one another in the blocking engagement. As a result of thevarious different dose setting positions, several co-operating guidesand/or several locating elements are provided, of which at least onepair is in the blocked engagement in each of the dose setting positions.The guide or the locating element may be rigidly formed on the conveyingmechanism, may be integral with it, or may be disposed on the conveyingmechanism so as to be displaceable. The complementary element formed bythe dose metering mechanism may be rigidly formed on the dose meteringmechanism, may be integral with it, or may be disposed on the dosemetering mechanism so as to be displaceable. In the case of adisplaceable arrangement, the guide and the locating element perform there-setting movement relative to one another and, in addition, a movementtransverse to the re-setting movement as they move into the blockingengagement. The same applies as they move out of the blockingengagement.

The engagement between the guide and the locating element may bereleased when the conveying mechanism is in the release position or maybe provided in the form of a releasable catch engagement, which mayadvantageously also constitute at the same time the releasable catchengagement for the dose selection when the conveying mechanism is in therelease position. In the latter variant, the blocking engagement becomesweaker during the movement into the release position up to the catchengagement; conversely, the catch engagement prevailing in the releaseposition becomes stronger relative to the blocking engagement during there-setting movement of the conveying mechanism.

In some preferred embodiments, the guide or several guides may beprovided in the form of a guide groove or projecting guide web, whichmay extend over virtually the entire path length of the re-settingmovement of the conveying mechanism. If the locating element is rigid,the guide or the several guides may extend as close as possible to thelocating element when the conveying mechanism assumes the releaseposition. In the release position, if the locating element or theseveral locating elements are in a releasable catch engagement with theguide or the several guides, the guide or the several guides extendaccordingly across a longer distance.

In some preferred embodiments, the dose metering movement comprises arotating movement of the dose metering mechanism relative to theconveying mechanism about a rotation axis. The dose metering movementmay be a purely rotating movement. It may also be a super-imposedmovement involving a rotating movement and a movement in translation,and, this being the case, along the rotation axis. In some embodiments,the conveying movement of the conveying mechanism comprises a movementof the conveying mechanism relative to the dose metering mechanism alongthe rotation axis. More particularly, the conveying movement may be apurely linear movement along the rotation axis. In such embodiments, itmay be that one of the structures, e.g., the conveying mechanism or thedose metering mechanism, at least partially surrounds the other aboutthe rotation axis and the requisite number of guides and/or locatingelements are disposed on casing surfaces of the conveying mechanism andthe dose metering mechanism lying opposite one another. The one of thetwo structures which at least partially surrounds the other, in somepreferred embodiments, the dose metering mechanism, is or comprises asleeve body and forms the at least one guide or the several guides onits inner casing surface.

In some embodiments, the conveying mechanism may be made as a singlepart, but it also may made up of several parts. In the case of themulti-part design, it comprises a conveying element which performs theconveying movement and thus acts directly on the product contained inthe reservoir, and a drive mechanism which is coupled to the conveyingelement, causing its conveying movement. The drive mechanism comprisesan output element and a drive element which can be moved relative to oneanother and are coupled to one another so that a driving movement of thedrive element causes an output movement of the output element. Theoutput element may be rigidly connected to the conveying element or iscoupled to the conveying element so that the output movement of theoutput element causes the conveying movement. The output element simplydrives the conveying element with it during its output movement. Thedrive element is mounted so that it is able to perform the drivingmovement on the one hand and perform a movement opposite the directionof the driving movement into the triggering position of the conveyingmechanism on the other hand. The drive element and the output elementare coupled to one another so that the drive element drives the outputelement with it during the driving movement, whereas the driving elementperforms the movement in the opposite direction without the outputelement. Drive mechanisms of this type are known from injection pens,for example as disclosed in patent specifications WO 97/36625 and DE 19900 792 C2. Also suitable would be a drive mechanism of the typedescribed in patent specification DE 199 45 397 C2, for example, wherebythe output element is smooth and the drive element has locating elementswhich press into the smooth external surface of the output element. Themovements of the conveying mechanism, and in the multi-part design themovements of the elements of the conveying mechanism, comprise or arelinear movements along a translation axis of the conveying mechanism.

In some embodiments, if, as is preferable, the dose metering mechanismconstitutes the at least one guide, it is of advantage if its dosesetting stop is not disposed at the end of the at least one guide but isdisposed at another point of the dose metering mechanism. If, as in somepreferred embodiments, the dose metering mechanism has the at least onelocating element, the at least one locating element does not form thedose setting stop of the conveying mechanism but is provided in additionto it. Otherwise, the at least one locating element may indeedconstitute the dose setting stop, including if the complementary stop,also referred to as the dose setting stop, is formed at the end of theat least one guide needed for the dose metering operation.

In some preferred embodiments, the conveying mechanism is designed formanual activation. However, it may also have a motorized drive whichcauses the conveying movement and is triggered when the conveyingmechanism is in the triggering position. In both embodiments, it has anoperating element, in the one instance for manual activation and causingthe conveying movement and in the other instance for triggering themotorized drive. In the case of manual activation, which may bepreferable for applications involving injection devices, the userapplies the force needed to produce the conveying movement by means ofthe operating element.

The longer activation path of the operating element compared with theconveying movement can be achieved on the basis of a gear mechanismwhereby the movement of the operating element is constantly andcontinuously reduced in the conveying direction by means of a reducinggear. Not least for reasons of simplicity, however, the activation pathof the operating element comprises a free movement of the operatingelement without any conveying movement and a joint movement of theoperating element with the conveying movement 1:1.

In some preferred embodiments, the operating element either forms theguide, which comprises several individual guides, or the locatingelement which may likewise be formed by several locating elements. Theoperating element and the guide formed by it or the locating elementformed by it may be made in a single piece. Alternatively, the guide orthe locating element is connected to the operating element via a link,i.e. is displaceable relative to the operating element. The articulatedconnection is designed so that it converts a movement of the operatingelement into a movement of the guide or the locating element into andalso back out of the blocking engagement. The relevant movement of theoperating element is a movement which is performed relative to aconveying element of the conveying mechanism acting on the product. Itis advantageous if said free movement of the operating element causesthe blocking engagement to be established and also released.

In some preferred embodiments, a cam link, including one with twoengaged link elements, can constitute the link connection. The at leasttwo link elements of the cam link slide as the movement of the operatingelement is converted into the movement of the guide or the locatingelement. The sliding may be one off the other, although in principle,the movement of the joint may be a rolling or sliding-rolling movement.

In some embodiments, the operating element may be connected via thelocating element to a conveying element of the conveying mechanism as itperforms its conveying movement. If the locating element isarticulatingly connected to the operating element, it is may also bearticulatingly connected to the conveying element or to another elementof the conveying mechanism which transmits the movement of the operatingelement to the conveying element. A rotating link is for the second linkconnection in this instance. Alternatively or in addition to a secondlink connection, the ability of the locating element to move may beobtained on the basis of the material and/or elastic design of thelocating element.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an injection device,

FIG. 2 illustrates a drive and dose metering module for the injectiondevice illustrated in FIG. 1.

FIG. 3 illustrates the drive and dose metering module in a releasedstate ready for selecting a dose,

FIG. 4 illustrates the drive and dose metering module with the doseselection blocked,

FIG. 5 illustrates the drive and dose metering module in a trigger-readystate,

FIG. 6 illustrates the drive and dose metering module after dispensingthe selected dose,

FIG. 7 illustrates the drive and dose metering module in the releasedstate ready for selecting the next dose,

FIG. 8 shows a detail of the module in the state illustrated in FIG. 3,

FIG. 9 shows a detail of the module in the state illustrated in FIG. 4,

FIG. 10 shows a detail of the module in the state illustrated in FIG. 5,

FIG. 11 shows a proximal portion of a modified drive and dose meteringmodule in the released state ready for selecting a dose,

FIG. 12 illustrates the modified drive and dose metering module in thereleased state, and

FIG. 13 illustrates the modified drive and dose metering module duringthe changeover to the trigger-ready state.

DETAILED DESCRIPTION

FIG. 1 shows an exemplary injection device in the form of a injectionpen with a toothed rack. The injection device has a two-part housing 1comprising a distal (or forward or front) housing portion and a proximal(or back or rear) housing portion which are fixedly connected to oneanother, for example screwed together. A housing compartment of thehousing 1 forming its distal housing portion contains a reservoir 2.Attached to a distal outlet of the reservoir 2 is an injection needle N.The longitudinal axis of the injection needle N forms a centrallongitudinal axis R of the injection device. A plunger 3 closes off theproximal end of the reservoir 2. The plunger 3 is able to perform aconveying movement along the axis R onto the outlet of the reservoir 2in order to force product out of the reservoir 2. The reservoir 2 is acommercially available ampoule, filled with the product to beadministered, for example insulin.

The plunger 3 is a conveying element of a conveying mechanism actingdirectly on the product, which, in addition to the plunger 3, also hasan output element 4, a drive element 5 and an operating element 6. Dueto the fact that the conveying element is provided in the form of aplunger 3, the output element 4 acting directly on the plunger 3 is aplunger rod and will therefore be referred to as such below. When theconveying mechanism is activated, the plunger rod 4 also performs theconveying movement and thus forces the plunger 3 in the distaldirection. The plunger rod 4 is provided in the form of a toothed rackwith several rows of teeth extending in the direction of the axis Rwhich are respectively offset from one another along the axis R by lessthan one tooth pitch to make the dose selection finer. The drive element5 can be moved along the axis R in the distal and proximal direction.The drive element 5 and the plunger rod 4 are coupled to one another sothat the drive element 5 drives the plunger rod 4 with it as it moves inthe distal direction but performs the movement in the proximal directionwithout the plunger rod.

In the embodiment illustrated as an example, the coupling is broughtabout by the engagement of drivers in the rows of teeth of the plungerrod 4. The engagement is such that a movement of the plunger rod 4 inthe distal direction relative to the drive element 5 is prevented and amovement of the drive element 5 in the proximal direction relative tothe plunger rod 4 is permitted. To prevent the plunger rod 4 from beingdriven during the movement in the proximal direction, the proximalportion of the housing 1 forms a retaining mechanism 10 which, like thedriver of the drive element 5, engages in at least one, but in theembodiment illustrated as an example, two rows of teeth of the plungerrod 4 so that the plunger rod 4 can be moved relative to the housing 1in the distal direction but not in the proximal direction. This isachieved due to the fact that the teeth of the rows of teeth are of asaw-tooth shape. The proximal portion of the housing 1 provides a mountfor the plunger rod 4 as well as the drive element 5 so that theseelements of the conveying mechanism 3-6 are not able to perform anyrotating movements about the axis R relative to the housing 1.

For every injection, the injection device enables the free selection ofa product dose which can be administered. To select and set the productdose, a dose metering element 8 is provided, which is able to perform adose metering movement relative to the conveying mechanism, inparticular relative to its drive element 5. The proximal portion of thehousing 1 also accommodates the dose metering mechanism 8 in anappropriate manner for performing the dose metering movement. In theembodiment illustrated as an example, in which the dose meteringmovement is a rotating movement about the axis R, the rear portion ofthe housing 1 provides a mount for the dose metering mechanism 8enabling it to rotate about the axis R. The axis R therefore forms thetranslation axis for the conveying mechanism and the rotation axis forthe dose metering mechanism 8. When performing the dose meteringmovement, the dose mechanism element 8 can be moved between discretepre-defined dose setting positions in the form of catch positions. Tothis end, it sits in a releasable catch engagement with the proximalportion of the housing 1 in each of the dose setting positions. Asregards the dose metering mechanism 8, it should also be pointed outthat in the embodiment illustrated as an example, it is provided in theform of a sleeve body and surrounds the drive element 5 as well as theoperating element 6. The drive element 5 and the operating element 6 arelikewise each provided in the form of a sleeve body, whereby theoperating element 6 surrounds a proximal end portion of the driveelement 5 and projects out of the dose metering mechanism 8 in theproximal direction to permit manual activation of the conveyingmechanism. The drive element 5, finally, generally or substantiallysurrounds the plunger rod 4.

To set the product dose, the drive element 5 constitutes a dose settingstop 13 and the dose metering mechanism 8 a dose setting stop 27 lyingopposite the dose setting stop 13 in the proximal direction. The dosesetting mechanism 8 forms its dose setting stop 27 by means of a distalend face, which extends in a spiral about the axis R as described inpatent specification DE 199 00 792 C2. The drive element 5 forms itsdose setting stop 13 by means of a cam projecting radially outwards, theshape of which is adapted to the contour of the spiral-shaped dosesetting stop 27.

In the state illustrated in FIG. 1, the conveying mechanism has assumeda position in the housing 1 closest to the distal end. In this state,the product dose is set by means of the dose metering mechanism 8,whereby a portion of the dose setting stop 27 corresponding to thedesired product dose is moved along the axis R into the position lyingopposite the dose setting stop 13. The distance left between the dosesetting stops 13 and 27 as measured along the axis R in the relevantdose metering position corresponds to the path length, i.e. theconveying stroke, which the drive element 5 can cover together with theplunger rod 4 and the plunger 3 during the injection. After setting theproduct dose, the drive element 5 and, due to the engagement, theplunger rod 4 with it are pulled in the proximal direction by pulling onthe operating element 6 until the dose setting stop 13 makes contactwith the dose setting stop 27. The conveying mechanism then assumes atriggering position, from which a pressing force acting on the operatingelement 6 can be applied in the distal direction for the injection. Insome embodiments, e.g., the embodiment shown in FIG. 1, it is clear thatprior to the injection, the housing cap illustrated in FIG. 1, as wellas the needle guard cap, must be removed.

The proximal portion of the housing 1, the parts of the conveyingmechanism mounted by this portion and the dose metering mechanism 8fixedly connected to the housing portion except for the dose meteringmovement constitute a drive and dose metering module, of the type knownfrom patent specification DE 199 00 792 C2. This module may be replacedby a drive and dose metering module of the type provided by the presentinvention.

FIG. 2 illustrates an exemplary embodiment of a drive and dose meteringmodule in accordance with the present invention. Parts which fulfill thesame functions as those of the drive and dose metering module injectiondevice of FIG. 1 are denoted by the same reference numbers. Unlessspecific explanations about the drive and dose metering module providedby the present invention are given, the module may correspond to that ofthe injection device illustrated in FIG. 1.

In one embodiment, the drive and dose metering module of the presentinvention has a dose metering lock, which prevents the set product dosefrom being adjusted when the conveying mechanism is in the triggeringposition. The dose metering lock also prevents an adjustment being madeto the product dose during the movement of the conveying mechanism outof the release position into the triggering position, i.e. during there-setting movement. The dose metering lock is based on an engagementbetween the conveying mechanism and the dose metering mechanism 8, whichblocks dose metering movements of the dose metering mechanism 8 relativeto the conveying mechanism when the conveying mechanism is in thetriggering position and will therefore be referred to herein as ablocking (or locking) engagement.

To produce the dose metering lock, the conveying mechanism has severallocating elements 7 a in addition to the elements of the known conveyingmechanism. The embodiment illustrated as an example has two locatingelements 7 a, and the dose metering mechanism 8 is provided with severalguides 9. The guides 9 are formed on a casing internal surface of thedose metering mechanism 8. They each extend parallel with the axis R andare arranged evenly around said axis R. In one exemplary embodiment,they are provided in the form of guide webs projecting out from thecasing internal surface.

In the longitudinal section illustrated in FIG. 2, only one of thelocating elements 7 a is visible. The other locating element 7 acorresponds to the one illustrated. The locating element 7 a is able tomove radially relative to the drive element 5 and the operating element6. It is connected to the drive element 5 at a first link and to theoperating element 6 at a second link. The first link is a simple pivotlink. The drive element 5 forms a pin as the linking element 14 of thefirst link and the locating element 7 a form a bush as the link element21; more specifically, a half-pin and a half-bush constitute the twolink elements 14 and 21. The pivot axis of this link is directedtransversely to the axis R. The second link is a cam link. The locatingelement 7 a forms a slot-type guide 20 and the operating element 6 formsa locating element 17 of the second link. The cam link converts an axialmovement made by the operating element 6 during the re-setting movementrelative to the drive element 5 into a radial movement of the locatingelement 7 a. The radial movement is a pivoting movement about the pivotaxis formed by the link as the proximal portion of the locating element7 a forming the guide 20, as viewed form the pivot axis, is moved intothe blocking engagement of the guides 9 lying radially opposite. Themovement causing this movement of the locating element 7 a and performedby the operating element 6 relative to the drive element 5 correspondsto a free stroke of the conveying mechanism because this movement doesnot cause any re-setting movement of the drive element 5 relative to theplunger rod 4. The only things which move are the operating element 6axially in the proximal direction and the locating element 7 a, i.e. thetwo locating elements 7 a, in addition to the blocking engagement. Thenumber of guides 9 and their distribution about the axis R is such thatthe locating elements 7 a are each always engaged with at least one ofthe guides 9 in the triggering position and during the re-settingmovement of the operating element 6 in each of the possible dosemetering positions of the dose metering mechanism 8.

From the state of the module illustrated in FIG. 2, in which theconveying mechanism has assumed the triggering position, the set productdose can be conveyed directly and hence dispensed. Simply by applyingpressure to the operating element 6, the plunger rod 4 is moved in thedistal direction. The plunger rod 4 transmits its conveying movement tothe plunger 3, which therefore performs the same conveying movement inorder to dispense the product. As it is moved out of the triggeringposition, the operating element 6 pushes against the locating element 7a, which is moved outwards into the blocking engagement and in turnpushes the drive element 5 in the distal direction via the linkconnection. The drive element 5 finally transmits its axial movement tothe plunger rod 4 by means of its drivers engaging in the rows of teethof the plunger rod 4 and the latter pushes on the plunger 3, asdescribed above. This joint movement of the entire conveying mechanism3-7, the reference 7 indicating the locating elements 7 a, is restrictedby a conveying stop 11 formed by the housing 1 and a conveying stop 12formed by the drive element 5 as conveying stop 12 comes into contactwith conveying stop 11. When the two conveying stops 11 and 12 are inthe stop position and the operating element 6 is in the distal position,the blocking engagement between the conveying mechanism and the dosemetering mechanism 8 is released or at least loosened to the degree thatthe dose metering mechanism 8 is able to perform dose metering movementsrelative to the conveying mechanism, for which reason this axialposition will be referred to as the release position below.

For more details of the dose metering lock, in particular the blockingengagement, the locating elements 7 a and the way in which theyco-operate with the operating element 6, reference may also be made toFIGS. 8 to 10, which illustrate this part of the drive and dose meteringmodule in a three-dimensional view.

FIG. 10 illustrates the dose metering lock in the state illustrated inFIG. 2. For reasons of clarity, however, the proximal portion of thedrive element 5 connected to the locating elements 7 a is notillustrated. The link element 17 of the operating element 6 isillustrated particularly clearly. The link element 17, which forms thelocating element of the cam link 17, 20, is integrally formed on theoperating element 6, namely on its distal end. It forms a sleeve portionof the operating element 6 with a bead-type distal ridge extending aboutthe axis R, which engages in the guide 20 of the locating element 7 aand also in the guide 20 of the other locating element 7 a lyingdiametrically opposite by reference to the axis R. The guide 20 extendsaxially and is directed outwards from the proximal towards the distalend at an angle to the axis R. The guide 20 comprises a radially outerguide 22 and a radially inner guide 23 lying opposite the outer guide22. The link element 17 of the operating element 6 co-operates with thetwo guides 22 and 23. During the re-setting movement of the operatingelement, the link element 17 pushes against the outer guide 22 andhence, due to the inclination of the outer guide 22, the locatingelement 7 a in the blocking engagement. As it moves in the distaldirection, the link element 17 pushes against the inner guide 23 andthus pushes the locating element 7 a out of the blocking engagement dueto the inclination of the inner guide 23. At its distal end, the guide20 formed by the guides 22 and 23 is wider to enable the bead-type ridgeof the link element 17 to be accommodated when the conveying mechanism3-7 is in the release position. The slot-type guide 20 is open in theproximal direction, which facilitates establishing the link connection17, 20.

In its proximal region, the locating element 7 a is provided with anaxial locating groove 24 in its radial outer surface, which may best beseen from FIG. 8. In the blocking engagement illustrated in FIGS. 9 and10, one of the guides 9 engages in the groove 24 of the locating element7 a so that the dose metering mechanism 8 is not able to make dosemetering movements relative to the drive element transversely to theengagement guide 9 but is able to perform axial movements unhindered. Inthis connection, it should be pointed out that the locating elements 7 aare respectively connected to the drive element 5 so that they areprevented from turning about the axis R.

The locating element 7 a forms a coupling element, which transmits itsmovement to the drive element 5 when the operating element 6 isactivated. When pressure is applied to the operating element 6, it actsas a stop for the operating element 6. To transmit a re-setting movementof the operating element 6, the locating element 7 a engages behind theoperating element 6. In performing this engagement, the locating element7 a forms a coupling element 28, which is in the form of a hook in theembodiment illustrated as an example. The operating element 6 isprovided with a shoulder behind which the coupling element 28 is able toengage and this is provided as a recess in a casing internal surface oran orifice in the casing of the operating element 6 in the embodimentillustrated as an example. The coupling element 28 is formed on an armforming the inner guide 23 of the locating element 7 a. It projectsradially outwards. Due to the pivoting movement of the locating element7 a as the blocking engagement is established, the coupling element 28is pivoted into engagement with the shoulder of the operating element 6.Consequently, the locating element 7 a not only constitutes the locatingelement of the blocking engagement, it is also used as a pressingelement for conveying the product and as a pulling element when theconveying mechanism is being re-set.

The way in which an injection device equipped with the drive and dosemetering module proposed by the present invention operates will beexplained below with reference to an operating sequence illustrated inFIGS. 3-7. Reference should also be made to FIGS. 1 and 2 and to FIGS.8-10, which provide a more detailed illustration of how the individualelements co-operate. FIGS. 3-7 illustrate only the drive and dosemetering module but it is easy to imagine the front portion of thehousing 1 accommodating the reservoir 2 with the plunger 3.

FIG. 3 illustrates the drive and metering module in a state in which theconveying mechanism has assumed the release position relative to thehousing 1 and the dose metering mechanism 8. In the release position,the product dose to be administered is set by means of the dose meteringmechanism 8. For setting purposes, the dose metering mechanism 8 ismoved relative to the housing 1 about the axis R and relative to thedrive element 5 into the dose setting position corresponding to the doseto be set. As a result of the catch mechanism acting during the dosesetting movement, the user hears a clicking sound during the settingprocess. A latching action from one dose metering position to another isfelt by a person operating the device. In addition, a visual display ofthe product dose may be provided, although this is not illustrated. Oncethe desired product dose has been set, the injection device is “charged”by moving the conveying mechanism in the distal direction as far as thetriggering position. The re-setting movement is operated by pulling onthe operating element 6.

Like the movement of the conveying mechanism into the release position,the re-setting movement is divided into two phases. In a first phase ofthe re-setting movement, the operating element 6 is moved in theproximal direction relative to the housing 1, the dose meteringmechanism 8 and in particular also relative to the drive element 5. Thestroke, i.e. the path length, of this free movement is denoted by HL.The first phase of the re-setting movement is complete when theoperating element 6 is in abutment, i.e. engaged, with the couplingelement 28.

FIGS. 2-7 illustrate another possible way of restricting the freemovement, which causes the driving action during the rest of there-setting movement in addition to or as an alternative to the locatingelement 7 a used as a pulling element in the embodiment illustrated asan example. A stop of the drive element 5 provided for this purpose isformed on its casing external surface and is denoted by reference number15. The operating element 6 forms a complementary stop 18 in the form ofa stop ring or stop cam, which projects radially inwards from thesurrounding casing surface of the operating element 6.

The operating element 6 is hooked onto the dose metering mechanism 8 bymeans of the link element 17 accommodated in the wider region of theguide 20 and a hook element 25 of the locating element 7 a, so that itis not able to slide in the proximal direction under its own weightalready and a certain amount of pulling force has to be applied toperform the re-setting movement. The hook element 25 is provided on thelocating element 7 a, distally, at a distance from its pivot axis. Inthe release position, the locating element 7 a engages with a hookelement 26 of the dose metering mechanism 8 by means of its hook element25.

FIG. 4 illustrates the drive and dose metering module after completingthe first phase (free movement) of the re-setting movement, but beforestarting the second phase. The driver stop 18 has just made contact withthe driver stop 15. From this point, as the operating element 6 ispulled farther back, the drive element 5 is driven in the proximaldirection due to the contact between the driver stops 15 and 18. Thedrivers of the drive element 5 thus slide over the teeth of the plungerrod 4, which are prevented from moving in the proximal direction due tothe engagement of the retaining mechanism 10.

During the first phase of the re-setting movement, the link element 17of the operating element 6 slides along the outer guide 22 on thelocating element 7 a. Due to the fact that the contour of the outerguide 22 is inclined inwards in the proximal direction, the locatingelement 7 a tips about its pivot axis formed in the link connection 14,21 into the blocking engagement with the guides 9 lying opposite. Thetipping movement and the accompanying radial movement of the proximalportion of the locating element 7 a may be seen by comparing FIGS. 3 and4 and in particular by comparing FIGS. 8 and 9, which correspond toFIGS. 3 and 4. The locating elements 7 a are intrinsically stiff bodies.With the tipping movement of the engaging part of the locating element 7a disposed proximally with respect to the pivot axis into the blockingengagement, its hook element 25 disposed distally with respect to thepivot axis tips out of the hooked engagement with the dose meteringmechanism 8 so that the drive element 5 can be moved relative to thedose metering mechanism 8 and the housing 1 in the proximal direction.

Due to the movement of the link element 17 along the outer guide 22, thelocating element 7 a is moved so far into the blocking engagement thatit lies with a proximal abutment surface in front of a distal stopsurface of the operating element 6. As a result of the abutting contactobtained in this manner, the operating element 6 presses against thelocating element 7 a when there is a movement in the proximal directionand thus moves the drive element 5 via the locating element 7 a likewisein the proximal direction.

From the state illustrated in FIG. 4, the conveying mechanism will bemoved into the triggering position by continuing pulling on theoperating element 6. In this second phase of the re-setting movement,the operating element 6 drives the drive element 5 with it via thecoupling by means of the coupling element 28 and/or by means of thedriver stops 15 and 18. Apart from a brief initial phase during whichthe locating element 7 a is moving into the blocking engagement, theblocking engagement prevents any dose setting movement of the dosemetering mechanism 8 during the entire re-setting movement and inparticular also in the triggering position.

To increase the locking action to prevent incorrect doses from being setduring the initial phase of the re-setting movement as well, thelocating element 7 a may already engage in the oppositely lying guides 9when the conveying mechanism is in the release position but in areleasable catch engagement rather than a blocking engagement. Thiscatch engagement may simultaneously also be the catch engagement for thedose metering mechanism 8 during its dose metering movement. In anembodiment of this type, the locating element 7 a would not becompletely free of the guides 9 when the conveying mechanism is in therelease position as is the case with the embodiment illustrated as anexample, but would engage in one or more of the guides 9 less deeplythan in the blocking engagement. The locating element 7 a and/or theguides 9 would need to be shaped accordingly, for example with a roundedregion in a radially outer region in order to form the releasable catchengagement on the one hand and the non-releasable blocking engagement onthe other hand.

FIG. 5 illustrates the drive and dose metering module in a state inwhich the conveying mechanism assumes the triggering position. In thetriggering position, the dose setting stops 13 and 27 of the driveelement 5 and the dose metering mechanism 8 sit against one another inan abutting contact. To operate the conveying mechanism 3 and thusconvey and dispense the set product dose, a pressing force is applied tothe operating element 6 in the proximal direction. The operating element6 presses against the locating element 7 a in the proximal direction andalso against the drive element 5 via the locating element 7 a and itslink connection 14, 21 to the drive element 5. The operating element 6,the locating elements 7 a and the drive element 5 are therefore moved inthe proximal direction. Due to the driving engagement between the driveelement 5 and the plunger rod 4, the plunger rod 4 is moved jointly withthe drive element 5 and the plunger 3 jointly with the plunger rod 4 inthe proximal direction. This conveying stroke HF of the conveyingmechanism is restricted by the abutting contact of the stop pair 11 and12. The axial distance set between the conveying stops 11 and 12 whenthe conveying mechanism is in the release position (FIG. 3) correspondsto the conveying stroke HF, i.e. the path length which the plunger 3travels in order to dispense the set product dose.

FIG. 6 illustrates the drive and dose metering module at the end of thefull conveying movement. The stop pair 11 and 12 are in abuttingcontact. However, the operating element 6 has not yet assumed its distalend position relative to the drive element 5 and instead it is still inthe axial position relative to the drive element 5 which it assumesduring the conveying movement. Accordingly, the conveying mechanism andthe dose metering mechanism 8 are still in the blocking engagement. Thetransition from this state into the subsequent phase of the freemovement of the operating element is smooth. As this happens, the linkelement 17 firstly slides on the inner guide 23 (FIG. 10 for example) ofthe locating element 7 a, as a result of which the locating element 7 atips radially inwards out of the blocking engagement and in its distalregion radially outwards so that it hooks with the dose meteringmechanism 8.

FIG. 7 illustrates the drive and dose metering module with the conveyingmechanism back in the release position. The only difference comparedwith the state illustrated in FIG. 3 is that the plunger rod 4 is pushedin the distal direction relative to the drive element 5 by the axialpath length HF of the conveying movement. The device is now ready forselecting another dose or performing another charging operation whilstpreserving the set dose.

FIGS. 11-13 illustrate a proximal end portion of a modified drive anddose metering module which may incorporate the drive and dose meteringmodule of the injection device illustrated in FIG. 1 instead of themodule of the embodiment illustrated as a first example. The samereference numbers are used to denote parts of the modified module whichfulfill the same functions as those described above and reference may bemade to the explanations given above. The difference compared with theembodiment illustrated as a first example is that the locating elementsof the conveying mechanism are disposed rigidly on the operating element6. In this embodiment they are formed integrally with the operatingelement 6. To highlight the difference compared with the firstembodiment, the locating elements of the modified module are denoted byreference number 7 b. The locating elements 7 b project out from thecasing outer surface of the operating element 6 at a distal end portion.They are provided in the form of locating cams.

The dose metering mechanism 8, which again surrounds the operatingelement 6 and the drive element 5 about the axis R, is also providedwith guides 9 on its casing inner surface in its portion surrounding theoperating element 6, in the form of straight guide webs 9 extendingparallel with the axis R, between which the locating elements 7 b engagein the locking engagement and along which they move during there-setting movement. As far as the actual blocking engagement isconcerned, there is no difference compared with the drive and dosemetering module of the embodiment illustrated as a first example.However, when the conveying mechanism is in the release position, thelocating elements 7 b do not move radially under the guides 9 but moveradially at the same height in front of the guides 9 in the proximaldirection. In the release position, the locating elements 7 a alsoconstitute catch elements 25 for establishing a catch engagement with acatch element 26 of the dose metering mechanism 8. The catch elements 25and 26 fulfill the function of the hook elements 25 and 26 of the firstexemplary embodiment. In this embodiment, the catch elements 25 arerecesses, one each being provided for each locating element 7 b. Thecatch element 26 of the dose metering mechanism 8 is a circumferentiallyextending annular web, which engages in the recesses 25 of the locatingelements 7 b when the conveying mechanism 3-7 is in the releaseposition. Like the hooking mechanism of the first embodiment, this catchengagement can be released by pulling on the operating element 6.

FIGS. 11 and 12 illustrate the drive and dose metering module of thesecond embodiment shown as an example, with the conveying mechanism 3-7disposed in the release position, FIG. 11 showing the operating element6 in a perspective view and FIG. 12 showing a longitudinal section, alsoin a perspective view. FIG. 13 illustrates the modified module duringthe re-setting movement of the conveying mechanism, i.e. after the catchengagement of the catch elements 25 and 26 has been released, with thelocating elements 7 b already in the blocking engagement, each betweentwo adjacent guides 9.

Embodiments of the present invention, including preferred embodiments,have been presented for the purpose of illustration and description.They are not intended to be exhaustive or to limit the invention to theprecise forms and steps disclosed. Obvious modifications or variationsare possible in light of the above teachings. The embodiments werechosen and described to provide the best illustration of the principlesof the invention and the practical application thereof, and to enableone of ordinary skill in the art to utilize the invention in variousembodiments and with various modifications as are suited to theparticular use contemplated. All such modifications and variations arewithin the scope of the invention as determined by the appended claimswhen interpreted in accordance with the breadth they are fairly,legally, and equitably entitled.

1. A device for administering an injectable product, comprising: a) ahousing with a reservoir for the product; b) a conveying mechanismmoveable from a release position in which a product dose is able to beset to a triggering position and from the triggering position performs aconveying movement by which the set product dose is dispensed from thereservoir, wherein the conveying mechanism forms a locating element; andc) a dose metering mechanism for performing dose metering movements intodose setting positions, each predefined by a catch engagement, to setthe product dose when the conveying mechanism assumes the releaseposition, wherein the dose metering mechanism forms a guide extendingover an axial path length along which the locating element moves as theconveying mechanism moves from the release position to the triggeringposition, wherein d) the conveying mechanism is coupled to the dosemetering mechanism by a blocking engagement in the triggering positionand during the movement from the release position into the triggeringposition, said blocking engagement blocks the dose metering mechanismagainst dose metering movements away from a set dose setting position,wherein, e) in the set dose positions, the guide and the locatingelement are in a releasable catch engagement, and as the conveyingmechanism and locating element move from the release position to thetriggering position, the locating element is guided along the guide overthe axial path length and pivots radially relative to the guide toestablish the blocking engagement, wherein the guide and the locatingelement are free of one another when the conveying mechanism is in therelease position.
 2. The device as claimed in claim 1, wherein the dosemetering mechanism forms a dose setting stop adjustable by the dosemetering movement and which restricts the movement of the conveyingmechanism from the release position into the triggering position anddefines a path length of the conveying movement.
 3. The device asclaimed in claim 2, wherein several discrete stops jointly form theadjustable dose setting stop and for each dose setting position only oneor a group of the stops restricts the movement of the conveyingmechanism, at least one of the stops in each case provided for thesettable product doses which correspond to the dose setting positions.4. The device as claimed in claim 2, wherein the dose setting stopextends continuously with an inclination towards the direction of theconveying movement of the conveying mechanism.
 5. The device as claimedin claim 1, wherein the dose metering movement includes a rotatingmovement of the dose metering mechanism relative to the conveyingmechanism about a rotation axis, the conveying movement includes amovement of the conveying mechanism relative to the dose meteringmechanism along the rotation axis, one of the conveying mechanism anddose metering mechanism at least partially surrounds the other and theguide and the locating element are provided on mutually facing,oppositely lying surfaces of the conveying mechanism and the dosemetering mechanism.
 6. The device as claimed in claim 1, wherein thelocating element is connected to the conveying mechanism so that it,radially pivots by means of a link.
 7. The device as claimed in claim 1,wherein the conveying mechanism has a manually operable operatingelement, activation of which causes the conveying movement, and theoperating element and the locating element are formed together in asingle piece.
 8. The device as claimed in claim 6, wherein the conveyingmechanism has a manually operable operating element, activation of whichcauses the conveying movement, and the operating element is connected tothe locating element via another link which converts a movement of theoperating element performed on activation into a movement of thelocating element connected to the operating element via the link intothe blocking engagement.
 9. The device as claimed in claim 8, whereinthe another link is a cam link and a link element of the operatingelement and a link element of the locating element are moveable relativeto one another in the link in and opposite the direction of theconveying movement of the conveying mechanism.
 10. The device as claimedin claim 8, wherein the operating element causes at least one of theconveying movement of the conveying mechanism and the conveyingmechanism movement into the triggering position via the locating elementconnected to the operating element via the link.
 11. The device asclaimed in claim 1, wherein the conveying mechanism has a manuallyoperable operating element, activation of which causes the conveyingmovement, and a total path length of a movement which can be performedby the operating element on activation is longer than the path length ofthe conveying movement corresponding to the full dispensing of the setproduct dose.
 12. The device as claimed in claim 11, wherein theconveying mechanism has at least one conveying element disposed in thereservoir which performs the conveying movement, and the operatingelement is coupled to the conveying element so that it drives theconveying element with it over a part of the total path length of itsmovement and travels the other part of the total path length of itsmovement without the conveying element.
 13. The device as claimed inclaim 1, wherein the blocking engagement automatically releases when theconveying mechanism is moved into the release position.
 14. The deviceas claimed in claim 1, wherein the conveying mechanism moves into therelease position due to the conveying movement.
 15. The device asclaimed in claim 1, wherein the dose metering mechanism performs thedose metering movement in the direction of an increase and in thedirection of a reduction of the product dose.
 16. The device as claimedin claim 1, wherein the locating element is coupled to a drive elementof the conveying mechanism by a first link, the locating elementpivoting relative to the drive element at the first link in a radialdirection as the conveying mechanism moves to the triggering position.17. The device as claimed in claim 16, wherein the locating elementradially pivots relative to the drive element at the first link when theconveying mechanism moves into the release position to release theblocking engagement.
 18. The device as claimed in claim 17, wherein inthe release position, the locating element forms a catch element forestablishing the catch engagement with the dose metering mechanism. 19.The device as claimed in claim 17, wherein the guide and the locatingelement are free of one another when the conveying mechanism is in therelease position.
 20. The device as claimed in claim 16, wherein thedrive element of the conveying mechanism forms a half-pin as the firstlink and the locating element forms a half-bush for coupling to thehalf-pin.
 21. The device as claimed in claim 16, wherein the locatingelement is coupled to an operating element of the conveying mechanism bya second link, wherein the operating element forms a bead element as thesecond link and the locating element forms a slot-type guide forcoupling to the bead element as the locating element moves into theblocking engagement with the guide.
 22. The device as claimed in claim21, wherein the locating element forms a coupling element fortransmitting the conveying movement of the operating element to thedrive element, wherein the operating element comprises a shoulder behindwhich the coupling element engages during the conveying movement suchthat operating element, the locating elements and the drive element movein the dispensing direction.
 23. A device for administering aninjectable product, comprising: a) a housing with a reservoir for theproduct; b) a conveying mechanism moveable from a release position to atriggering position and from the triggering position performs aconveying movement by which a set product dose is dispensed from thereservoir; and c) a dose metering mechanism able to perform a dosemetering movement into dose setting positions, each predefined by acatch engagement, to set the product dose when the conveying mechanismassumes the release position, wherein d) the conveying mechanism iscoupled to the dose metering mechanism by a blocking engagement in thetriggering position and during the movement into the triggeringposition, said blocking engagement blocking the dose metering mechanismagainst dose metering movements in the respectively set dose position,wherein a guide formed by the dose metering mechanism and a locatingelement formed by the conveying mechanism sit in a releasable catchengagement with one another when the conveying mechanism is in therelease position, and the catch engagement becomes stronger during themovement of the conveying mechanism into the triggering position andestablishes the blocking engagement.
 24. The device as claimed in claim23, wherein the conveying mechanism has a manually operable operatingelement, activation of which causes the conveying movement, and in thatthe operating element is secured on one of the dose metering mechanismand the housing counter to the direction of the conveying movement bymeans of a releasable catch connection when the conveying mechanismassumes the release position.
 25. A device for administering aninjectable substance, comprising: a) a housing; b) a conveying mechanismmoveable from a release position to a triggering position from which theconveying mechanism performs a conveying movement to administer aselected amount of the substance; and c) a dose metering mechanism ableto perform dose metering movements to select the amount of the substanceto be administered when the conveying mechanism is in the releaseposition, wherein d) the conveying mechanism is coupled to the dosemetering mechanism in the triggering position and, during the movementinto the triggering position, dose metering movements by the dosemetering mechanism are prevented; e) the conveying mechanism furthercomprises at least one locating element projecting from an outer surfaceand the dose metering mechanism further comprises at least one guideformed by axially extending guide webs between which the at least onelocating element engage when the conveying mechanism moves from therelease position to the triggering position, wherein the guide and thelocating element are free of one another when the conveying mechanism isin the release position, and wherein f) the at least one locatingelement forms a catch element recess for establishing a catch engagementwith a circumferentially extending annular web of the dose meteringmechanism in the release position such that the web is guided by thecatch element recess during the dose metering movements, wherein thecatch engagement releases upon moving the conveying mechanism towardsthe triggering position.